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POPULAR SCIENCE REVIEW. 
credibly small apertures (generally, however, dying from internal 
injuries thus caused), and because they will gnaw through a stout 
wooden cage in one night, and devote every spare moment to this 
one purpose, with a pertinacity worthy of Baron Trenck. At all 
events, few have been brought alive to this country, and none 
have survived. At present (February, 1877) I have one which I 
have preserved since September last, defeating his attempts at 
escape by lining the cage with tin, and allowing him a plentiful 
supply of fresh water, in which he is always dabbling. With the 
approach of winter all his attempts to escape ceased, and I now 
always take the little stranger for an airing in my closed hands 
whilst his bed is being made and his room cleaned out. He seems 
to like this, but after a few minutes a gentle nibble at my finger 
testifies to his impatience, and if this be not attended to the 
Fig. 3. 
feet 
Section of Heimdalen showing the Lemmings’ track* which does not follow the 
watershed-.- 
biting progresses in a crescendo scale until it becomes unbear- 
able, although it has never under these circumstances drawn 
blood. My little prisoner shows few other signs of tameness, 
but the fits of jumping, biting, and snarling rage have almost 
ceased. I expect, however, that with the return of spring the 
migratory impulse will be renewed, and that he will kill him- 
self against the wires of his cage like a swallow. 
The reader is nowin a position to consider the three q ues tions 
raised by the above facts, and those questions are as follow : — 
1. Whence do the lemmings come? 2. Whither do they go ? 
3. Why do they migrate at all? With regard to the first, no 
one has yet supplied an answer. They certainly do not exist in 
my neighbourhood during the intervals of migration ; and the 
Kjolen range was probably selected as their habitat, not because 
